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  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 439 (2006), S. 187-191 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Methane is an important greenhouse gas and its atmospheric concentration has almost tripled since pre-industrial times. It plays a central role in atmospheric oxidation chemistry and affects stratospheric ozone and water vapour levels. Most of the methane from natural sources in Earth's ...
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2024-01-22
    Description: Natural gas is considered a bridging technology in the energy transition because it produces fewer carbon emissions than coal, for example. However, when leaks exist, methane is released into the atmosphere, leading to a dramatic increase in the carbon footprint of natural gas, as methane is a much stronger greenhouse gas than carbon dioxide. Therefore, we conducted a detailed study of methane emissions from gas‐powered end‐use appliances and then compared their climate impacts with those of electricity‐powered appliances. We used the Munich Oktoberfest as a case study and then extended the study to 25 major natural gas consuming countries. This showed that electricity has been the more climate‐friendly energy source at Oktoberfest since 2005, due to the extensive use of renewable electricity at the festival and the presence of methane emissions, particularly caused by the incomplete combustion and leakages of natural gas in cooking and heating appliances. By contrast, at the global level, our study shows that natural gas still produces lower carbon emissions for end‐user appliances than electricity in 18 of the 25 countries studied. However, as the share of renewable energy in the electricity mix steadily increases in most countries, the carbon footprint of electricity will be lower than that of natural gas in these countries in the near future. These findings from our comparison of the total carbon emissions of electric and gas‐powered end‐use appliances can help inform the debate on how to effectively address climate change.
    Description: Plain Language Summary: Although natural gas is considered a relatively climate‐friendly energy source compared to coal, leakage of methane, the main component of natural gas, can significantly increase the climate impact of natural gas. This is because methane is a very strong greenhouse gas. In this study, we focused on methane leakage from end‐use appliances used for cooking and heating. Using the Munich Oktoberfest as a case study, we found that these end‐use appliances produce significant methane emissions. Therefore, we investigated at which leakage rates and which electricity mixes it would be better to use electric appliances for cooking and heating instead to reduce overall carbon emissions. We found that despite leakage rates, natural gas is still more climate‐friendly than electricity in most countries around the world. However, as the share of renewable energy in the electricity mix increases in most countries, electricity is becoming a more climate‐friendly energy source every year. With this study, we want to make people aware of how the climate friendliness of electricity compares to natural gas over time.
    Description: Key Points: Methane emissions at Oktoberfest are measured and classified as natural gas‐based using isotopic analysis and the ratio of ethane to methane. Oktoberfest could save 87% of total carbon emissions from energy consumption if all gas‐powered appliances were replaced with electric ones. We aim to make people aware how the carbon footprint of electric and natural gas‐driven end‐user appliances compares and evolves over time.
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: ETH Zürich Foundation http://dx.doi.org/10.13039/501100012652
    Description: Technical University of Munich–Institute for Advanced Study
    Description: German Excellence Initiative
    Description: European Union Seventh Framework Programme
    Description: https://doi.org/10.14459/2022mp1663551
    Description: https://github.com/ankitshekhar99/Oktoberfest2019Study/tree/main
    Keywords: ddc:333.7 ; climate change ; methane ; carbon dioxide ; emissions ; carbon mitigation ; global
    Language: English
    Type: doc-type:article
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  • 3
    Publication Date: 2021-05-04
    Description: Atmospheric temperature and ozone photochemistry are recognised to play dominant roles in setting the abundance of 18O18O isotopologues (expressed via Δ36) of atmospheric oxygen. Here, we use the AC-GCM EMAC to simulate the abundance of atmospheric 18O18O in a most consistent to date kinetic chemistry modelling framework. Extensive model diagnostics allow us quantifying contribution of various factors into changes in Δ36 since the last 60 years. It is shown that atmospheric dynamics is another fundamental ingredient of atmospheric Δ36 distribution. We discuss potential applications of clumped O2 composition for quantifying various atmospheric processes like decadal changes in tropospheric O3 abundance or tropopause warming due to volcanism.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Format: text
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  • 4
    Publication Date: 2015-10-02
    Description: Samples from two Greenland ice cores (NEEM and NGRIP) have been measured for methane carbon isotope ratios ( δ 13 C-CH 4 ) to investigate the CH 4 mixing ratio anomaly during Greenland Interstadial (GI) 21.2 (85,000 years before present). This extraordinarily rapid event occurred within 150 years, comprising a CH 4 mixing ratio pulse of 150 ppb (∼25 %). Our new measurements disclose a concomitant shift in δ 13 C-CH 4  of 1 %0. Keeling Plot Analyses reveal the δ 13 C of the additional CH 4  source constituting the CH 4 anomaly as -56.8±2.8 %0, which we confirm by the means of a previously published box model. We propose tropical wetlands as the most probable additional CH 4 source during GI-21.2 and present independent evidence that suggests tropical wetlands in South America and Asia have played a key role. We find no evidence that boreal CH 4 sources, such as permafrost degradation, contributed significantly to the atmospheric CH 4 increase, despite the pronounced warming in the Northern Hemisphere during GI-21.2.
    Print ISSN: 0886-6236
    Electronic ISSN: 1944-9224
    Topics: Biology , Chemistry and Pharmacology , Geography , Geosciences , Physics
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  • 5
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    PANGAEA
    In:  Supplement to: Egger, Matthias; Rasigraf, Olivia; Sapart, Célia-Julia; Jilbert, Tom; Jetten, Mike S M; Röckmann, Thomas; van der Veen, Carina; Bânda, Narcisa; Kartal, Boran; Ettwig, Katharina; Slomp, Caroline P (2015): Iron-Mediated Anaerobic Oxidation of Methane in Brackish Coastal Sediments. Environmental Science & Technology, 49(1), 277-283, https://doi.org/10.1021/es503663z
    Publication Date: 2023-01-13
    Description: Methane is a powerful greenhouse gas and its biological conversion in marine sediments, largely controlled by anaerobic oxidation of methane (AOM), is a crucial part of the global carbon cycle. However, little is known about the role of iron oxides as an oxidant for AOM. Here we provide the first field evidence for iron-dependent AOM in brackish coastal surface sediments and show that methane produced in Bothnian Sea sediments is oxidized in distinct zones of iron- and sulfate-dependent AOM. At our study site, anthropogenic eutrophication over recent decades has led to an upward migration of the sulfate/methane transition zone in the sediment. Abundant iron oxides and high dissolved ferrous iron indicate iron reduction in the methanogenic sediments below the newly established sulfate/methane transition. Laboratory incubation studies of these sediments strongly suggest that the in situ microbial community is capable of linking methane oxidation to iron oxide reduction. Eutrophication of coastal environments may therefore create geochemical conditions favorable for iron-mediated AOM and thus increase the relevance of iron-dependent methane oxidation in the future. Besides its role in mitigating methane emissions, iron-dependent AOM strongly impacts sedimentary iron cycling and related biogeochemical processes through the reduction of large quantities of iron oxides.
    Keywords: GEMAX; GNC_X; Gulf of Bothnia, Baltic sea; US5B
    Type: Dataset
    Format: application/zip, 2 datasets
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  • 6
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    PANGAEA
    In:  Supplement to: Egger, Matthias; Lenstra, Wytze K; Jong, Dirk; Meysman, Filip J R; Sapart, Célia-Julia; van der Veen, Carina; Röckmann, Thomas; Gonzales, S; Slomp, Caroline P (2015): Rapid sediment accumulation results in high methane effluxes from coastal sediments. PLoS ONE, 11(8), e0161609, https://doi.org/10.1371/journal.pone.0161609
    Publication Date: 2023-01-13
    Description: Will be submitted by the author
    Keywords: GCUWI; Gravity corer, UWITEC; Grevelingen Lake, Netherlands; Scharendijke_Site
    Type: Dataset
    Format: application/zip, 3 datasets
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  • 7
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    PANGAEA
    In:  Supplement to: Egger, Matthias; Kraal, Peter; Jilbert, Tom; Sulu-Gambari, Fatimah; Sapart, Célia-Julia; Röckmann, Thomas; Slomp, Caroline P (2016): Anaerobic oxidation of methane alters sediment records of sulfur, iron and phosphorus in the Black Sea. Biogeosciences, 13(18), 5333-5355, https://doi.org/10.5194/bg-13-5333-2016
    Publication Date: 2023-01-13
    Description: The surface sediments in the Black Sea are underlain by extensive deposits of iron (Fe) oxide-rich lake sediments that were deposited prior to the inflow of marine Mediterranean Sea waters ca. 9000 years ago. The subsequent downward diffusion of marine sulfate into the methane-bearing lake sediments has led to a multitude of diagenetic reactions in the sulfate-methane transition zone (SMTZ), including anaerobic oxidation of methane (AOM) with sulfate. While the sedimentary cycles of sulfur (S), methane and Fe in the SMTZ have been extensively studied, relatively little is known about the diagenetic alterations of the sediment record occurring below the SMTZ. Here we combine detailed geochemical analyses of the sediment and pore water with multicomponent diagenetic modeling to study the diagenetic alterations below the SMTZ at two sites in the western Black Sea. We focus on the dynamics of Fe, S and phosphorus (P) and demonstrate that diagenesis has strongly overprinted the sedimentary burial records of these elements. Our results show that sulfate-mediated AOM substantially enhances the downward diffusive flux of sulfide into the deep limnic deposits. During this downward sulfidization, Fe oxides, Fe carbonates and Fe phosphates (e.g. vivianite) are converted to sulfide phases, leading to an enrichment in solid phase S and the release of phosphate to the pore water. Below the sulfidization front, high concentrations of dissolved ferrous Fe (Fe2+) lead to sequestration of downward diffusing phosphate as authigenic vivianite, resulting in a transient accumulation of total P directly below the sulfidization front. Our model results further demonstrate that downward migrating sulfide becomes partly re-oxidized to sulfate due to reactions with oxidized Fe minerals, fueling a cryptic S cycle and thus stimulating slow rates of sulfate-driven AOM (~ 1-100 pmol/cm**3/d) in the sulfate-depleted limnic deposits. However, this process is unlikely to explain the observed release of dissolved Fe2+ below the SMTZ. Instead, we suggest that besides organoclastic Fe oxide reduction, AOM coupled to the reduction of Fe oxides may also provide a possible mechanism for the high concentrations of Fe2+ in the pore water at depth. Our results reveal that methane plays a key role in the diagenetic alterations of Fe, S and P records in Black Sea sediments. The downward sulfidization into the limnic deposits is enhanced through sulfate-driven AOM with sulfate and AOM with Fe oxides may provide a deep source of dissolved Fe2+ that drives the sequestration of P in vivianite below the sulfidization front.
    Type: Dataset
    Format: application/zip, 12 datasets
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  • 8
    Publication Date: 2023-02-07
    Keywords: Acid volatile sulfides; Chromium reducible sulfur; DEPTH, sediment/rock; GEMAX; GNC_X; Gulf of Bothnia, Baltic sea; Iron; Iron, total; Iron/Aluminium ratio; Porosity; Sulfur, total; US5B
    Type: Dataset
    Format: text/tab-separated-values, 309 data points
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  • 9
    Publication Date: 2023-02-07
    Keywords: DATE/TIME; DEPTH, sediment/rock; GCUWI; Gravity corer, UWITEC; Grevelingen Lake, Netherlands; Porosity; Scharendijke_Site
    Type: Dataset
    Format: text/tab-separated-values, 29 data points
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  • 10
    Publication Date: 2023-02-07
    Keywords: Acid volatile sulfides; Chromium reducible sulfides; DATE/TIME; DEPTH, sediment/rock; GCUWI; Gravity corer, UWITEC; Grevelingen Lake, Netherlands; Iron; Iron, total; Iron oxides; Molybdenum; Sample comment; Scharendijke_Site; Sulfur, total; Thorium-232
    Type: Dataset
    Format: text/tab-separated-values, 1364 data points
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